Accelerometer; Connectivity; Functionality - Digilent Basys MX3 Reference Manual

Basys MX3™ Board Reference Manual

10 Accelerometer

Basys MX3 provides an onboard accelerometer: NXP's MMA8652FCR1. It is a 3-axis, 12-bit digital accelerometer,
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exposing an I C digital interface. It is possible to use its ACL_INT2 pin for raising a programmable interrupt.
The accelerometer is located on the top of the board; you can recognize the arrows that show the directions of the
three axes.
The Fig. 10.1 shows the way Accelerometer is controlled using digital signals.

10.1 Connectivity

The accelerometer is connected to SCL1 and SDA1 lines of the I
INT2 pin.
Schematic Name
SCL
SDA
ACL_INT2

10.2 Functionality

To use the accelerometer, proper I
interface must be initialized, and then accessed through read and write functions. The I
accelerometer is 0x1D.
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Communication over the I C is implemented in the ACL library of the Basys MX3 library pack. If the user wants to
use the accelerometer without the ACL library, they must implement their own I
The accelerometer has a set of registers that can be written to configure the device and read to access the data
collected by the accelerometer.
Note that you can visualize the communication with the accelerometer by attaching a logic analyzer to the 8-pin
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I C connector, located on the top of the board.
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Figure 10.1. Accelerometer schematic diagram.
PIC32 pin
SCL1/RG2
SDA1/RG3
RPG0/PMD8/RG0
Table 10.1. Accelerometer connectivity.
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C communication (read, write) must be implemented over I
2
C1 interface. A general I/O signal is connected to
Description
I2C Clock signal
I2C Data signal
Programmable Interrupt
2
C device address of the
2
C functions.
2 2
C1. The I C1
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